Bottom Line:
Exceptionally large surface area and well-defined nanostructure are both critical in the field of nanoporous carbons for challenging energy and environmental issues.The tailor-made pore structure of hollow carbon nanospheres enables target-oriented applications, as exemplified by their enhanced adsorption capability towards organic vapours, and electrochemical performances as electrodes for supercapacitors and sulphur host materials for lithium-sulphur batteries.The facile approach may open the doors for preparation of highly porous carbons with desired nanostructure for numerous applications.

ABSTRACTExceptionally large surface area and well-defined nanostructure are both critical in the field of nanoporous carbons for challenging energy and environmental issues. The pursuit of ultrahigh surface area while maintaining definite nanostructure remains a formidable challenge because extensive creation of pores will undoubtedly give rise to the damage of nanostructures, especially below 100 nm. Here we report that high surface area of up to 3,022 m(2) g(-1) can be achieved for hollow carbon nanospheres with an outer diameter of 69 nm by a simple carbonization procedure with carefully selected carbon precursors and carbonization conditions. The tailor-made pore structure of hollow carbon nanospheres enables target-oriented applications, as exemplified by their enhanced adsorption capability towards organic vapours, and electrochemical performances as electrodes for supercapacitors and sulphur host materials for lithium-sulphur batteries. The facile approach may open the doors for preparation of highly porous carbons with desired nanostructure for numerous applications.

f1: Schematic illustration of preparation of HCNs.(a) Fabrication of conventional HCNs by a tedious templating method. This method usually includes preparation of a predesigned core template, adsorption and polymerization of raw materials of polymeric shell, carbonization, additional activation sometimes and removal of hard templates. For the as-obtained conventional HCNs, their BET surface areas are very difficult to exceed 1,800 m2 g−1 and their diameters are very hard to decrease down to 100 nm. (b) Design and fabrication of novel HCNs through a facile procedure without any tedious templating and activation steps. This is achieved via the simple carbonization treatment of well-orchestrated PACP hollow spheres. For the resulting new HCNs, their BET surface areas can be up to 3,022 m2 g−1 with a uniform diameter as low as 69 nm.

Mentions:
Hollow carbon nanospheres (HCNs), a class of intriguing nanoporous carbon materials, have received much research interest by virtue of the special shape, low density and large interior void space fraction, allowing their many potential applications242526272829. The key to the success in applications strongly depends on the ability to design well-defined HCNs, coupled with highly porous structures. In general, templating strategy involving hard/soft templates could be the most frequently used technique to prepare HCNs, which involves coating carbon precursor onto a predesigned solid spherical core template, carbonization, activation sometimes and removal of the template (Fig. 1a)242526. This strategy allows for fine control of hollow cores by selection of different template sizes. Nevertheless, surface modification of template is generally required for uniform coating. The removal of template is often needed for hard templating, which seems time-consuming, severe and harmful to the environment (for example, silica template with hydrofluoric acid etching), whereas for soft templating, the thermo-decomposable soft template can be directly removed during carbonization. Furthermore, it is very difficult to control the diameter of HCNs below 100 nm, a size that is essential to many valuable nanoscale effects. This is because small core templates tend to aggregate seriously, leading to ill-defined hollow structures. More importantly, the SSAs of HCNs reported so far are relatively low (typically ≤1,800 m2 g−1; Supplementary Table 1). This might be attributed to the collapse of the hollow structure upon intensive pore-making treatment. The low SSAs not only render HCNs at a disadvantage in gas sorption but also deteriorate their performances in energy storage, guest encapsulation, catalysis and so on. Thus, the nanospherical diameter below 100 nm and SSA beyond 1,800 m2 g−1 represent a largely unfilled gap for HCNs.

f1: Schematic illustration of preparation of HCNs.(a) Fabrication of conventional HCNs by a tedious templating method. This method usually includes preparation of a predesigned core template, adsorption and polymerization of raw materials of polymeric shell, carbonization, additional activation sometimes and removal of hard templates. For the as-obtained conventional HCNs, their BET surface areas are very difficult to exceed 1,800 m2 g−1 and their diameters are very hard to decrease down to 100 nm. (b) Design and fabrication of novel HCNs through a facile procedure without any tedious templating and activation steps. This is achieved via the simple carbonization treatment of well-orchestrated PACP hollow spheres. For the resulting new HCNs, their BET surface areas can be up to 3,022 m2 g−1 with a uniform diameter as low as 69 nm.

Mentions:
Hollow carbon nanospheres (HCNs), a class of intriguing nanoporous carbon materials, have received much research interest by virtue of the special shape, low density and large interior void space fraction, allowing their many potential applications242526272829. The key to the success in applications strongly depends on the ability to design well-defined HCNs, coupled with highly porous structures. In general, templating strategy involving hard/soft templates could be the most frequently used technique to prepare HCNs, which involves coating carbon precursor onto a predesigned solid spherical core template, carbonization, activation sometimes and removal of the template (Fig. 1a)242526. This strategy allows for fine control of hollow cores by selection of different template sizes. Nevertheless, surface modification of template is generally required for uniform coating. The removal of template is often needed for hard templating, which seems time-consuming, severe and harmful to the environment (for example, silica template with hydrofluoric acid etching), whereas for soft templating, the thermo-decomposable soft template can be directly removed during carbonization. Furthermore, it is very difficult to control the diameter of HCNs below 100 nm, a size that is essential to many valuable nanoscale effects. This is because small core templates tend to aggregate seriously, leading to ill-defined hollow structures. More importantly, the SSAs of HCNs reported so far are relatively low (typically ≤1,800 m2 g−1; Supplementary Table 1). This might be attributed to the collapse of the hollow structure upon intensive pore-making treatment. The low SSAs not only render HCNs at a disadvantage in gas sorption but also deteriorate their performances in energy storage, guest encapsulation, catalysis and so on. Thus, the nanospherical diameter below 100 nm and SSA beyond 1,800 m2 g−1 represent a largely unfilled gap for HCNs.

Bottom Line:
Exceptionally large surface area and well-defined nanostructure are both critical in the field of nanoporous carbons for challenging energy and environmental issues.The tailor-made pore structure of hollow carbon nanospheres enables target-oriented applications, as exemplified by their enhanced adsorption capability towards organic vapours, and electrochemical performances as electrodes for supercapacitors and sulphur host materials for lithium-sulphur batteries.The facile approach may open the doors for preparation of highly porous carbons with desired nanostructure for numerous applications.

ABSTRACTExceptionally large surface area and well-defined nanostructure are both critical in the field of nanoporous carbons for challenging energy and environmental issues. The pursuit of ultrahigh surface area while maintaining definite nanostructure remains a formidable challenge because extensive creation of pores will undoubtedly give rise to the damage of nanostructures, especially below 100 nm. Here we report that high surface area of up to 3,022 m(2) g(-1) can be achieved for hollow carbon nanospheres with an outer diameter of 69 nm by a simple carbonization procedure with carefully selected carbon precursors and carbonization conditions. The tailor-made pore structure of hollow carbon nanospheres enables target-oriented applications, as exemplified by their enhanced adsorption capability towards organic vapours, and electrochemical performances as electrodes for supercapacitors and sulphur host materials for lithium-sulphur batteries. The facile approach may open the doors for preparation of highly porous carbons with desired nanostructure for numerous applications.